Current File : //usr/lib/python3/dist-packages/hamcrest/core/core/raises.py
import re
import sys
from typing import Any, Callable, Mapping, Optional, Tuple, Type, cast
from weakref import ref
from hamcrest.core.base_matcher import BaseMatcher
from hamcrest.core.description import Description
from hamcrest.core.matcher import Matcher
__author__ = "Per Fagrell"
__copyright__ = "Copyright 2013 hamcrest.org"
__license__ = "BSD, see License.txt"
class Raises(BaseMatcher[Callable[..., Any]]):
def __init__(
self,
expected: Type[Exception],
pattern: Optional[str] = None,
matching: Optional[Matcher] = None,
) -> None:
self.pattern = pattern
self.matcher = matching
self.expected = expected
self.actual: Optional[BaseException] = None
self.function: Optional[Callable[..., Any]] = None
def _matches(self, function: Callable[..., Any]) -> bool:
if not callable(function):
return False
self.function = cast(Callable[..., Any], ref(function))
return self._call_function(function)
def _call_function(self, function: Callable[..., Any]) -> bool:
self.actual = None
try:
function()
except BaseException:
self.actual = sys.exc_info()[1]
if isinstance(self.actual, self.expected):
if self.pattern is not None:
if re.search(self.pattern, str(self.actual)) is None:
return False
if self.matcher is not None:
if not self.matcher.matches(self.actual):
return False
return True
return False
def describe_to(self, description: Description) -> None:
description.append_text("Expected a callable raising %s" % self.expected)
def describe_mismatch(self, item, description: Description) -> None:
if not callable(item):
description.append_text("%s is not callable" % item)
return
function = None if self.function is None else self.function()
if function is None or function is not item:
self.function = ref(item)
if not self._call_function(item):
return
if self.actual is None:
description.append_text("No exception raised.")
elif isinstance(self.actual, self.expected):
if self.pattern is not None or self.matcher is not None:
description.append_text("Correct assertion type raised, but ")
if self.pattern is not None:
description.append_text('the expected pattern ("%s") ' % self.pattern)
if self.pattern is not None and self.matcher is not None:
description.append_text("and ")
if self.matcher is not None:
description.append_description_of(self.matcher)
description.append_text(" ")
description.append_text('not found. Exception message was: "%s"' % str(self.actual))
else:
description.append_text(
"%r of type %s was raised instead" % (self.actual, type(self.actual))
)
def describe_match(self, item, match_description: Description) -> None:
self._call_function(item)
match_description.append_text(
"%r of type %s was raised." % (self.actual, type(self.actual))
)
def raises(exception: Type[Exception], pattern=None, matching=None) -> Matcher[Callable[..., Any]]:
"""Matches if the called function raised the expected exception.
:param exception: The class of the expected exception
:param pattern: Optional regular expression to match exception message.
:param matching: Optional Hamcrest matchers to apply to the exception.
Expects the actual to be wrapped by using :py:func:`~hamcrest.core.core.raises.calling`,
or a callable taking no arguments.
Optional argument pattern should be a string containing a regular expression. If provided,
the string representation of the actual exception - e.g. `str(actual)` - must match pattern.
Examples::
assert_that(calling(int).with_args('q'), raises(TypeError))
assert_that(calling(parse, broken_input), raises(ValueError))
assert_that(
calling(valid_user, bad_json),
raises(HTTPError, matching=has_properties(status_code=500)
)
"""
return Raises(exception, pattern, matching)
class DeferredCallable(object):
def __init__(self, func: Callable[..., Any]):
self.func = func
self.args: Tuple[Any, ...] = tuple()
self.kwargs: Mapping[str, Any] = {}
def __call__(self):
self.func(*self.args, **self.kwargs)
def with_args(self, *args, **kwargs):
self.args = args
self.kwargs = kwargs
return self
def calling(func: Callable[..., Any]) -> DeferredCallable:
"""Wrapper for function call that delays the actual execution so that
:py:func:`~hamcrest.core.core.raises.raises` matcher can catch any thrown exception.
:param func: The function or method to be called
The arguments can be provided with a call to the `with_args` function on the returned
object::
calling(my_method).with_args(arguments, and_='keywords')
"""
return DeferredCallable(func)
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